Osmium is an element with numerous useful physical and chemical properties. Osmium is the densest known element and possesses an extremely high hardness comparable to diamond. Wear-resistant osmium alloys are used in the construction of many devices such as fountain pen tips and electrical contacts. Osmium is also used as a contrast agent for staining and fixing lipids prior to visualization using transmission electron microscopy.
Osmium is also a useful material in the production of radioisotopes. Osmium-192 or osmium-189 may also be irradiated on a cyclotron to produce Re-186, a radioisotope with many potential applications to nuclear imaging methods and therapeutic compositions. Osmium-190 may be irradiated in a thermal neutron flux to produce the radioactive isotope Os-191. Os-191 decays to Ir-191m, another radioisotope that is an excellent source of x-rays. Os-191/Ir-191m radioisotope generation systems may be used to provide Ir-191m radioisotope for dynamic radiotracer studies such as angiography.
Due to the toxicity of osmium, medical technologies that make use of osmium are limited in the amount of osmium they may use. In order to minimize the amount of osmium necessary to achieve the desired effect, a higher purity of osmium may be desirable. Existing techniques of producing chemically pure osmium typically involve nitric acid oxidation of a mixture containing the osmium and the fusion of the Os metal with KNO3/KOH at high temperatures. Unless the mixture is made up of finely divided particles, the nitric acid oxidation may be a lengthy process. During the purification of osmium radioisotopes, the lengthy process times may expose technicians to extensive dosages of hazardous ionizing radiation.
A need in the art exists for a method of separating an amount of osmium from a mixture of the osmium and at least one other metal in a relatively short time compared to existing methods without need for high temperatures. Such a process may be used to produce chemically pure osmium samples in a shorter time using relatively simple chemical reactions and equipment. The shortened process times further limit the exposure of technicians to potentially hazardous conditions, particularly in the production of chemically pure osmium radioisotopes.